OF-40

The OF-40 MBT was designed from 1977 by Otobreda and FIAT specifically for the export market. Otobreda was responsible for overall design and production and Fiat the power pack. In appearance the OF-40 resembles the late-production German Leopard 1A4 and it uses some components of the Leopard 1 MBT. The first prototype of the OF-40 (O for Otobreda, F for FIAT and 40 for the approximate weight in tons) was completed in 1980.

The United Arab Emirates placed an order for 18 OF-40 Mk 1s and the first of these was delivered in 1981. Since then, the United Arab Emirates has taken delivery of a further 18 OF-40 Mk 2 MBTs and three armoured recovery vehicles, while the original 18 OF-40 Mk 1 MBTs have been brought up to Mk 2 standard.

The OF-40 MBT has also been tested in Thailand, demonstrated in Egypt and offered for local production in Spain and Greece. The Otobreda OF-40 MBT is no longer being marketed and the only customer to date is the United Arab Emirates (Dubai).

Description

The all-welded steel hull is divided into three compartments: driving at the front, fighting in the centre and engine and transmission at the rear. The driver is seated at the front on the right side and has a single-piece hatch cover that lifts and swings to the left. There are three unity periscopes in front of him, the centre one of which can be replaced by an Alenia image intensification periscope for night driving. To the left of the driver is the NBC pack and 42 rounds of 105 mm ammunition and behind him there is an oval emergency hull escape hatch.

The all-welded steel turret is in the centre of the hull with the commander and gunner on the right and the loader on the left. The commander has a circular hatch cover that opens to the rear and eight unity periscopes for all-round observation, one of which can be replaced by an Alenia image intensification periscope. The commander's seat can be elevated by a manually operated hydraulic system and a foot-operated valve will enable the commander lower the seat quickly in an emergency.

The commander does not have a cupola, but mounted in the roof forward of the hatch is a day/night sight from Officine Galileo, developed in a joint venture with SFIM of France. This is stabilised and fitted with image intensification night vision equipment. This enables the tank commander to detect and identify the target which can then either be handed over to the gunner or engage the target personally.

The gunner is seated in front of and below the commander and has one forward-facing roof-mounted periscope and an optical sight, the Alenia C215 articulated telescope with a 7.5° field of view and a magnification of x8. It is mounted coaxially with the 105 mm gun in an M114 telescope mount.

The loader sits on the left of the turret and has a circular hatch cover that opens to the rear, in front of which are two roof-mounted periscopes that give observation to the front and left side.

The main armament of the OF-40 is an Otobreda-designed and -manufactured 105 mm 52 calibre rifled tank gun with falling wedge breech block, concentric buffer and spring recuperator. The gun is fired electrically but can also be fired by a manually actuated impulse generator. During counter-recoil the automatic breech block opens and ejects the spent cartridge case into a bag under the breech.

The barrel is provided with a thermal sleeve and a bore evacuator. The gun fires all standard NATO 105 mm ammunition including APDS, canister, HEAT, HESH and smoke and a well-trained crew can achieve a rate of fire of 9 rds/min. As an option the main armament can be stabilised in both elevation and traverse.

A total of 57 rounds of 105 mm ammunition is carried, 42 to the left of the driver and 15 in the turret for ready use.

A 7.62 mm or 12.7 mm machine gun is mounted coaxially to the left of the main armament and a similar weapon is mounted on the turret roof for anti-aircraft use.

Mounted externally on either side of the turret are four electrically operated smoke grenade dischargers.

The fire-control system has been designed by Officine Galileo and consists ofthe gunner's fire-control system, gunner's telescope which moves in elevation with the main armament, commander's stabilised day/ night roof-mounted sight and the turret/gun electrohydraulic drive system.

The gunner's fire-control system consists of an Officine Galileo OG14 sight with a magnification of x8 and range scale for APDS, HEAT and HESH 105 mm projectiles and 7.62 mm machine gun ammunition; Alenia VAQ-33 laser range-finder with a range of between 400 and 9,995 m; laser feeding and control equipment; fire-control computer; control device and readout for the tank commander, gunner's controls and elevation sensor.

The commander's roof-mounted VS 580-B sight can be traversed through a full 360°, has a magnification of x8, a stadiametric rangefinding capability and range scales for APDS, HEAT and HESH ammunition.

Turret traverse and gun elevation are electrohydraulic, with turret traverse at a rate of 360° in 17 seconds and gun elevation from -9 to +20° at 7c/s. The turret/gun drive system is controlled from the gunner's handle but an override system allows the commander to take over the laying and firing of the main armament if required and manual controls are provided for emergency use.

The engine, transmission and cooling system are assembled to form the power pack which can be removed by four personnel with a crane in under 45 minutes. The cables and wires are provided with quick disconnect couplings and, if required, the power pack can be run outside the vehicle for testing.

The engine is an MTU 10-cylinder, four-stroke, precombustion chamber, supercharged multi-fuel developing 830 hp at 2,200 rpm and is fitted with a tropicalisation kit to control the fuel supply and prevent the engine from overheating.

Two fuel tanks, with a total capacity of 1,000 litres, are mounted each side ofthe engine compartment and fuel can be drawn from one or both tanks.

Combustion air is taken in by two supercharged blowers through the two air cleaners. The two dry air cleaners are fitted in the side recess in front of the engine compartment and air enters through the intake scoops on the hull deck. Screens mounted in front of the scoops prevent large particles such as leaves entering the vehicle. A cyclone filter battery cleans the air of coarse dust and large-surfaced micro-top filters retain the fine dust. The coarse dust ejected by the cyclone filters is continuously blown outside by a dust blower installed in each air cleaner. The exhaust gases are taken from each cylinder liner by flexible corrugated tube compensators through an exhaust manifold into the exhaust mufflers in the side recesses of the engine compartment.

The engine of the OF-40 is liquid cooled through a self-contained cooling system with internal pressure controlled by a pressure relief and underpressure valve. On either side of the transmission is a cooler with a control fan on the vertical axis between them to suck the necessary cooling air from the top through the cooling air intake grille and force it through the two coolers. When deep fording, this duct is filled with water and the fan and coolers are therefore completely flooded.

Engine torque is transmitted to a torque converter which is followed by a four-speed planetary gearbox with two reverse speeds. The individual speeds are shifted electrohydraulically by a shift lever alongside the driver. There is a separate clutch between the engine and ZF transmission which can be operated manually from the crew compartment. This provides easy starting at low temperatures as the starter has to crank the engine only and not the transmission.

The steering works through a longitudinally superimposed gearbox, so steering movements do not cause essential power losses in the gearbox. Steering movements are mechanically transmitted from the control handle at the driver's station to the control valve.

The final drives are on either side at the rear of the vehicle and are of the planetary type. The transmission is connected to the final drives by an internally toothed sleeve which can be loosened from the outside when the power pack has to be removed.

The suspension is of the torsion bar type with seven dual rubber-tyred roadwheels on each side. The first three and last two roadwheels have hydraulic shock-absorbers and bump stops to prevent excessive wheel travel. The adjustable idler is at the front, drive sprocket at the rear and there are five track support return rollers on each side.

The track is the rubber-bushed connector type with the individual track shoes joined by end connectors and centre guiding teeth. The upper part of the track and suspension is covered by a steel-reinforced rubber skirt which keeps dust down and provides a degree of protection against attack by HEAT projectiles.

The OF-40 has three independent braking systems; service, parking and emergency systems.

The tank can ford to a depth of 1.2 m without preparation and an optional semi-deep fording hydraulic system enables it to cross streams to a maximum depth of 2.25 m. A snorkel can be fitted which enables the OF-40 to ford to a depth of 4 m. An electrically operated bilge pump is fitted in both the engine and crew compartment, each with a capacity of 120 litres/min.

The overpressure NBC system is mounted at the front ofthe hull to the left ofthe driver. Fresh air is drawn into the vehicle by a blower and is then separated from the coarse dust in a cyclone filter. The NBC protection filter is downstream of the coarse dust filter and retains all known NBC agents. The dust collection compartment of the cyclone filter is continuously kept free of dust by a dust "ejector blower. Pressure in the tank is monitored by a pressure gauge in the crew compartment.

An automatic fire extinguishing system in the engine compartment has spray tubes and nozzles connected to a battery of bottles in the crew compartment containing the fire extinguishing agent. This system is activated at 180°C through a firewire in the engine compartment.

Variants

OF-40 Mk 2 MBT

The OF-40 Mk 2 MBT is essentially the Mk 1 fitted with the Galileo OG14L2A fire-control system which includes a stabilisation system for the 105 mm gun and sensors for wind velocity, powder temperature, ambient temperature and type of ammunition. The OG14L2B is similar but has a stabilised line of sight.

In the OF-40 Mk 2 the tank commander has a day/ night periscope that is self-stabilised during panoramic search and slaved to the gun stabilisation when used for firing.

The gunner has a sight with a magnification of x7 and x14 that incorporates a laser range-finder as well as a telescopic sight, with a magnification of x8, coaxial with the 105 mm gun.

Mounted externally on the right side of the mantlet is an LLLTV camera with the monitor in the turret.

Deliveries of the second batch of 18 OF-40 Mk 2 tanks began in 1984 and were completed in 1985. The Mk 1 tanks have now been brought up to Mk 2 standard.

OF-40/120 Mk 2A MBT

This vehicle is no longer being marketed.

Systems on OF-40 Chassis

The hull of the OF-40 can also be used to mount other weapon systems such as a twin 35 mm anti-aircraft turret similar to the one on the Gepard anti-aircraft gun system. The OF-40 chassis, with a different power pack, is also used as the basis for the Otobreda Palmaria 155 mm self-propelled howitzer described later in this book. The Palmaria chassis also forms the basis for the 76 mm OTOMATIC self-propelled air defence system. Details of the OTOMATIC are given in Jane's Land-Based Air Defence 1999-2000, pages 59 to 60. As of early 1999 the OTOMATIC system remained at the prototype stage.

Status

Production complete. In service with Dubai (part of the United Arab Emirates).